A. Field of the Invention
The present invention relates to a method and apparatus for cutting optical fibers, and more particularly,, to a method and apparatus for successively scribing and breaking an optical fiber along a plane either oblique or perpendicular to its axis.
B. Description of the Prior Art
One of the major uses of fiber optics is long distance wide band communications. In this utilization, fiber optics surpasses coaxial cable in every respect; it offers wider band widths over greater distances without repeaters, uses no scarce or expensive materials, and has complete freedom from both cross-talk between parallel lines and electromagnetic interference. Eventually, it is expected that the installed cost of systems using fiber optic data transmission will be lower than for any form of wire data transmission.
Particularly in long distance wide band data transmission, single optical fibers are being used almost exclusively in preference to bundles of fibers. The single fiber transmission path consists of a single fiber of glass or fused silica, usually between 16 and 100 microns in diameter. When two such fibers interface with transmitting or receiving devices or are joined in a splice or with connectors, the end surfaces must be finished optically smooth and perpendicular to the fiber axis in order to achieve low coupling loss. Fiber optic cable is normally supplied by its manufacturers in the form of spooled stock, much the same as wire and the installation of connectors and the making of splices is left to the user. Frequently, this work must be done under highly adverse conditions such as in manholes where the procedures must be kept simple and the results must be of good quality and repeatable.
Single fibers are usually cut by the "scribe-and-break" technique. In general, this technique is performed by nicking or scribing the fiber at one point on its circumference with a diamond or tungsten carbide knife edge. Thereafter, sufficient tension is applied to cuase a fracture. This is very similar to the age-old technique used for cutting glass rod and tubing for laboratory applications. Although it sounds simple, the actual mechanization of this technique to produce satisfactory results requires extremely uniform fibers and very exact control of the scribe depth, applied tension, and bend radius, if any. Control of these parameters is sufficiently difficult that, even under laboratory conditions, it is frequently necessary to repeat the process several times in order to produce a surface of acceptable quality at the fracture. In general, the fracture simply propagates in an uncontrolled manner through the path of least resistance and an ideal perpendicular flat surface is seldom obtained.
Another disadvantage of the prior art "scribe-and-break" technique is that when an acceptable quality surface cut is obtained, the circumferential edge is very sharp. This sharp edge frequently causes chipping when an installation of the fiber into a connector is made. Frequently upon insertion of the fiber into the connector, the edge is fractured or the connector material is shaved and a miniscule chip lodges itself in between the fiber and connector causing a bad connection.
The herein disclosed invention has an inherent advantage which avoids the occurrence of a sharp edge; instead it produces a beveled or rounded corner between the outer surface of the fiber and the obtained surface of the perpendicular or oblique plane of the cut.
A similar method and/or apparatus performing high quality cutting of an optical fiber has not been observed in the prior art.